Laser Processing in Liquid With Gas Bubble Detection and Avoidance
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Solution Overview
Problem
Gas bubbles formed during laser processing in liquid environments cause undesirable interactions with laser radiation, leading to reduced processing speed and quality due to reflection and refraction effects at the gas-liquid interface.
Innovation Solution
A method involving detection of gas bubbles using a detection unit, followed by an initial action to prevent or reduce their interaction with the laser beam, including actions such as altering fluid flow, generating ultrasonic waves, or adjusting laser radiation to avoid or detach the bubbles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser processing is performed in liquid environment, then cooling effect and processing precision are improved, but gas bubbles form causing reflection and refraction of laser radiation
Solution Approach 1:
The system performs preliminary detection of gas bubbles in the liquid path using a detection unit (camera, photodiode, or oxygen sensor) before the laser beam reaches the processing area. When bubbles are detected, the system preemptively adjusts liquid flow or activates ultrasonic generators to remove bubbles from the laser path, preventing reflection and refraction issues before they occur.
Solution Approach 2:
The system continuously monitors the liquid environment for gas bubbles using detection units and provides real-time feedback to the control unit. Based on this feedback, the control unit dynamically adjusts liquid circulation flow rates or activates ultrasonic bubble removal mechanisms, creating a closed-loop control system that maintains optimal processing conditions.
2Reliability
If liquid circulation is increased to remove bubbles, then bubble removal efficiency is improved, but processing time increases
Solution Approach 1:
Instead of continuously circulating liquid at high flow rates, the system applies liquid flow adjustments or ultrasonic activation only partially - specifically when and where gas bubbles are detected in the laser path. This targeted approach removes bubbles efficiently without the continuous high-flow circulation that would slow down overall processing.
Solution Approach 2:
The system uses periodic detection and reactive bubble removal rather than continuous high-intensity liquid circulation. The detection unit continuously monitors, and when bubbles are detected, the system periodically activates flow adjustment or ultrasonic removal mechanisms only for the duration needed to clear the bubbles, thereby maintaining high processing speed while ensuring bubble removal when necessary.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Significantly reduces disruptive effects of gas bubbles, enhancing processing speed and quality by minimizing laser radiation interference.
Implementation Method 1
detecting a gas bubble in a predefined detection area using a detection unit
Implementation Method 2
They can also circulate through the system multiple times due to fluid exchange, thereby repeatedly disrupting the laser processing. Regardless of the specific type of gas bubble, it is always the case that those gas bubbles located within the effective range of the laser radiation cause an undesirable interaction with the laser radiation. This is due to the different refractive indices of air and liquid, which leads to unwanted reflection and refraction of the laser radiation at the interface between the liquid and the gas bubble.
Implementation Method 3
This is due to the different refractive indices of air and liquid, which leads to unwanted reflection and refraction of the laser radiation at the interface between the liquid and the gas bubble.
Implementation Method 4
flow adjustments, ultrasonic waves, or redirecting the laser beam to avoid or eliminate gas bubbles from the processing area
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3
AI summary
The invention relates to a method for laser processing of workpieces in liquid, the method comprising the following steps: – providing a workpiece (22) in a process chamber (20) filled with a liquid; – focusing pulsed laser radiation (14) on a surface of the workpiece (22) using a focusing unit (18); – producing a relative movement between the focused laser radiation and the workpiece surface (22a) using a positioning unit (16); – detecting a gas bubble (28) in a predefined detection region using a detection unit (30); and – carrying out a first action to avoid or reduce interaction effects between the laser radiation (14) and the detected gas bubble (28).